BFS

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 #include <queue>  
 6 using namespace std;  
 7   
 8 struct node  
 9 {  
10     int x,y,step;  
11 };  
12   
13 char map[105][105];  
14 bool vis[105][105];  
15 int dir[4][2]= {{1,0},{-1,0},{0,1},{0,-1}};  
16 int n,m,sx,sy,ex,ey,ans;  
17   
18 int check(int x,int y)  
19 {  
20     if(x<0 || x>=n || y<0 || y>=m)  
21         return 1;  
22     if(vis[x][y] || map[x][y]=='#')  
23         return 1;  
24     return 0;  
25 }  
26   
27 void bfs()  
28 {  
29     int i;  
30     queue<node> q;  
31     node a,next;  
32     a.x = sx;  
33     a.y = sy;  
34     a.step = 0;  
35     vis[a.x][a.y]=true;  
36     q.push(a);  
37     while(!q.empty()){  
38         a = q.front();  
39         q.pop();  
40         if(map[a.x][a.y]=='E'){  
41             ans = a.step;  
42             return ;  
43         }  
44         for(i = 0;i < 4; i++){
45             next.x = a.x + dir[i][0];  
46             next.y = a.y + dir[i][1];  
47             if(check(next.x,next.y)) continue;  
48             next.step = a.step + 1;  
49             vis[next.x][next.y] = true;  
50             q.push(next);  
51         }  
52     }
53     ans = -1;
54 }  
55   
56 int main()  
57 {  
58     int t;  
59     cin>>t;  
60     while(t--){  
61         cin>>n>>m; 
62         for(int i = 0;i < n;i++)  
63             scanf("%s",map[i]);  
64         for(int i = 0;i < n;i++){  
65             for(int j = 0;j < m;j++){  
66                 if(map[i][j]=='S'){  
67                     sx = i;  
68                     sy = j;  
69                 }  
70             }  
71         }  
72         memset(vis,0,sizeof(vis));  
73         bfs();  
74         cout<<ans<<endl;
75     }
76     return 0;  
77 }